Syringe.



P. II. MUELROY.

SYRINGE.

APPLIOATION FILED nu 1v, 190s.

919,918, Patented Apnz?, 1909.

rn: NoRRls PETERS co., wAsmNcroN, n. c.

Nhenthe packing has become stuck by narran srafrnis rarnnr armen PATRICK J. MCELROY', OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO THE RANDALL-FAICHNEY COMPANY, OF, BOSTON, MASSACHUSETTS, A CORPORATION OF MAS- SACHUSETTS.

SYRINGE.

Specification o Letters Patent.

Application led May 1, 1908. Serial No. 430,257.

No. 919,918. Patented April 27, 1909.

To all whom it may concern.' long inaction, it is very difficult to Vstart it Be it known that I, PATRICK J. MoELnoY, l by pressure in a longitudinal direction. of Cambridge, in the county of MiddlesexV Frequently the-pressure necessary to overand State of Massachusetts, have invented come the adhesion is so great that when the certain new and useful Improvements in piston is once started, it acquires a greater Syringes, of which the following is a specification. o

This invention relates to syringes and has particular reference to the pistons or plungers used in connection therewith to eject the contents thereof.

It has for its object which is carried by the 1 ston `and causes the contents, andso produces a pressure in the syringe suiiicient to burst the barrel. Again, it is diilicult to apply a starting pressure of so great an amount in a straight line, and so iirm a grip is necessary to be taken on the syringe barrel to react against this starting y pressure that there is great danger of crushlatter to fit tightly wit n the barrel of the ing the barrel and snapping the stem of the syringe, to be united to the piston in such a piston rod.

way that it cannotI turn or twist relatively The easiest way in which to free the packto the piston rod, but must partake of any ing from the barrel is to turn it rotarily by rotary movement which may be given to the twisting the piston-rod, but with syringe latter. pistons as hitherto constructed, it has not It is the present practice to put up quanbeen practicable to do this, for the reason tities of medicinal preparations such as antithat the rod is usually smooth where it eX- toxins and serums, in glass syringes which tends through the packing, and the latter is are sealed up, and are ready for instant use not secured to it in any way. Consequently, by simply breaking the seal. These syringes turning of the rod will simply cause it to rocontain pistons which consist of rods eXtendtate within the packing while the latter reing and moving longitudinallyv within the .mains in as iirm adhesion as before to the barrel of the syringe. Such rods yare 4walls of the barrel. It has been proposed packed so that they will iit tightly within to provide the rod with small spurs engaging the syringe barrels and will expel all the portions of the packing, but" these are incontents thereof by` compressible antiseptic adequate for the purpose stated. packing which surrounds a part of the pis- By my invention, I have devised a conton rod and usually takes the form of a cord struction of piston-rod which enables the wound repeatedly about the rod until the diameter is suflicient to cause it to fit tightly within the walls of the barrel. Such syringes when filled and packed away are sometimes allowed to remain unused for months, during which time the pistonpacking, having remained stationary, adheres more or less tightly to the syringe barrel; Much difficulty has been experienced in freeing the packing by a rotary movement of the piston so that the piston could subsequently be moved to expel the contents of the syringe, and prior to the present invention, no sure means of securing this result had been devised. Y

The syringes hitherto, made have had packings which were held in such a way that they could not be displaced longitudinally of the rod, but heretofore the construction has been such that thepacking can be practically moved within the syringe barrel only by a longitudinal movement of the piston.

to enable the packing that 'relative rotation between the piston rod and packing is impossible. That is, whenever the piston-rod is turned, the packing must turn with it. It is impossible for the adhesion or friction between the packing and'barrel to displace the former laterally when either the barrel or piston-rod is r0- tated.

My invention therefore consists in the construction of the piston-rod whereby the packing is so securely attached thereto that it cannot turn thereon, this construction being described and claimed in the following specification, and illustrated in the accompanying drawings, in which,-

`Figure 1 represents anv elevation. of a syringe piston-rod embodying the features of this invention. Fig. 2 represents an elevation of the same as seen with the rod turned at right angles to the position of Fig. 1. Fig. Srepresents a sectional view illustrating the piston-rod having the packing applied velocity than the rate of discharge of the packing to be fastened to it in such a way thereto and mounted within a syringe barrel. Fig. i represents a perspective view of a piston-rod having a slightly modified con struction.

The saine reference characters indicate the same parts in all the figures.

rlhe essence of the invention resides in the formation or con'liguration o1 that end ci' the piston-rod which is contained within the barrel of the syringe.

a represents the barrel oi any suitable or ordinary torni of syringe, and l) repres .its a piston-rod which is capable of sliding Within the barrel. The inner end portion oi this piston is surrounded by a packing c which preferably consists of a cord of .il-en ble and compressible material such as asbestos or the like, which is inade antis "ic and is wound about the rod to a thickness great enough to make it 'lit tightly within the syringe barrel and prevent leakage oi5 liquid or air. At the end of the piston-rod, and some distance back from the end, Hanges c and f are formed upon the rod. The space between these fianges contains the packing and the flanges serve to prevent the latter being displaced endwise.

ln order to hold the packing so that it will not slip transversely or rotarily on the piston-rod, l provide the latter between the flanges with an aperture g of which there may be one or more, as desired. Such aperture forms an eye through which the cord is passed as it is being wound upon the rod. The strands of the cord which pass through the eye of course hold the packing and pevent it slipping upon the piston when the latter is turned and the outer surface of the packing is pressed against the inner surface of the barrel.

In order to hold the packing still more securely, the rod between the flanges is given a non-circular shape or conguration, this portion or' the rod being flattened or otherwise formed. This flattening causes wing-s h and i to bulge out from opposite sides, while between these wings the rod is recessed, as at y' and 7c in Fig. 2. lfilhen the packing is tightly wound upon this flattened and widened portion of the rod, and is filled in between convolutions ot' the cord so that its outer periphery is cylindrical, it presses so tightly upon the flattened sides that the latter cannot turn within it, and any rotary movement of the rod must necessarily be imparted to the packing.

In Sonie cases the eye or aperture g maybe Y dispensed with and the flattening ot the rod relied upon alone to give the necessary grip for the packing. Such a construction is shown in Fig. 4. Conversely, the flattening of the rod may be dispensed with, and the eye may be formed in a circular section and be employed alone to hold the packing.

l claim zl. In a syringe, a piston-rod having abutments, packing filling the space between the abutments and prevented thereby from being displaced endwise, and the piston-rod being provided with an aperture through which part of the packing is passed, whereby the )aching is restrained also from lateral disp aceinent.

2. ln a syringe, a piston consisting ol a rod movable endwise within the barrel of the syringe; and a pecking surrounding thc rod to rit the interior of the barrel, said rod having one or more apertures through which part of the packing extends und by which the packing is prevented lrom rotating on the rod.

3. A syringe comprising :t tubular barrel, a piston-rod movable endwisc therein, and a packing consisting oil cord wound about said rod to a diameter equal to that of the interior ot the barrel, the rod having` one or more apertures through which the cord is passed, nf'hereby the picking is prevented from being displaced.

4. A syringe comprising a tubular lnn'rel, a piston-rod movable cndwise therein, and :1 packing surrmuiding :i part ol.1 said rod and iitting the interior of said barrel, the rod being of non-circular cross-section. where surrounded by the peeking, whereby the latter is held and prevented troni becoming displaced when the rod is rotated.

A syringe comprising a tubular barrel, piston-rod movable endwise therein having separated lateral Allunges near its inner end and being 'flattened and widened between seid iianges, and a packing surrounding the rod between the liauges, being held by the latter against endn'ise displacement und by said flattened portion ol the rod from rele.- tive rotary displacement.

6. A syringe comprising u tubular barrel, a piston-rod movable eudwise therein haring' separated lateral ilunges nein' its inner end, said rod being llattencd and widened for u portion oi the distance between said [langes and havi an aperture through such flattened portion, and :i packing surrounding the rod betweeen thc llanges and extending into such aperture, icing restrained by the flanges from endwise displacement und by the configuration of the rod and the aperture from rotation relatively to the rod, whereby rotation oi" the lutter within the barrel will also turn the packing to lree the sume from the walls of the barrel.

in testimony whereof l: have aliixed my signature, in presence of two witnesses.

PTll EK J. MC-ELROY.

lllitnesses:

C. F. BROWN, P. lll. Pnzznrri.

Elf) 

